Re: [PATCH v2 2/5] accel/thames: Add driver for the C7x DSPs in TI SoCs

[Andrew Davis <afd@ti.com>]

On 1/14/26 2:46 AM, Tomeu Vizoso wrote:
> Some SoCs from Texas Instruments contain DSPs that can be used for
> general compute tasks.
> 
> This driver provides a drm/accel UABI to userspace for submitting jobs
> to the DSP cores and managing the input, output and intermediate memory.
> 
> Signed-off-by: Tomeu Vizoso <tomeu@tomeuvizoso.net>
> ---
>   Documentation/accel/thames/index.rst |  28 +++++
>   MAINTAINERS                          |   9 ++
>   drivers/accel/Kconfig                |   1 +
>   drivers/accel/Makefile               |   3 +-
>   drivers/accel/thames/Kconfig         |  26 +++++
>   drivers/accel/thames/Makefile        |   9 ++
>   drivers/accel/thames/thames_core.c   | 155 ++++++++++++++++++++++++++
>   drivers/accel/thames/thames_core.h   |  53 +++++++++
>   drivers/accel/thames/thames_device.c |  93 ++++++++++++++++
>   drivers/accel/thames/thames_device.h |  46 ++++++++
>   drivers/accel/thames/thames_drv.c    | 155 ++++++++++++++++++++++++++
>   drivers/accel/thames/thames_drv.h    |  21 ++++
>   drivers/accel/thames/thames_ipc.h    | 204 +++++++++++++++++++++++++++++++++++
>   drivers/accel/thames/thames_rpmsg.c  | 155 ++++++++++++++++++++++++++
>   drivers/accel/thames/thames_rpmsg.h  |  27 +++++
>   15 files changed, 984 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/accel/thames/index.rst b/Documentation/accel/thames/index.rst
> new file mode 100644
> index 0000000000000000000000000000000000000000..ca8391031f226f7ef1dc210a356c86acbe126c6f
> --- /dev/null
> +++ b/Documentation/accel/thames/index.rst
> @@ -0,0 +1,28 @@
> +.. SPDX-License-Identifier: GPL-2.0-only
> +
> +============================================================
> + accel/thames Driver for the C7x DSPs from Texas Instruments
> +============================================================
> +
> +The accel/thames driver supports the C7x DSPs inside some Texas Instruments SoCs
> +such as the J722S. These can be used as accelerators for various workloads,
> +including machine learning inference.
> +
> +This driver controls the power state of the hardware via :doc:`remoteproc </staging/remoteproc>`
> +and communicates with the firmware running on the DSP via :doc:`rpmsg_virtio </staging/rpmsg_virtio>`.
> +The kernel driver itself allocates buffers, manages contexts, and submits jobs
> +to the DSP firmware. Buffers are mapped by the DSP itself using its MMU,
> +providing memory isolation among different clients.
> +
> +The source code for the firmware running on the DSP is available at:
> +https://gitlab.freedesktop.org/tomeu/thames_firmware/.
> +
> +Everything else is done in userspace, as a Gallium driver (also called thames)
> +that is part of the Mesa3D project: https://docs.mesa3d.org/teflon.html
> +
> +If there is more than one core that advertises the same rpmsg_virtio service
> +name, the driver will load balance jobs between them with drm-gpu-scheduler.
> +
> +Hardware currently supported:
> +
> +* J722S
> diff --git a/MAINTAINERS b/MAINTAINERS
> index dc731d37c8feeff25613c59fe9c929927dadaa7e..a3fc809c797269d0792dfe5202cc1b49f6ff57e9 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7731,6 +7731,15 @@ F:	Documentation/devicetree/bindings/npu/rockchip,rk3588-rknn-core.yaml
>   F:	drivers/accel/rocket/
>   F:	include/uapi/drm/rocket_accel.h
>   
> +DRM ACCEL DRIVER FOR TI C7x DSPS
> +M:	Tomeu Vizoso <tomeu@tomeuvizoso.net>
> +L:	dri-devel@lists.freedesktop.org
> +S:	Supported
> +T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
> +F:	Documentation/accel/thames/
> +F:	drivers/accel/thames/
> +F:	include/uapi/drm/thames_accel.h
> +
>   DRM COMPUTE ACCELERATORS DRIVERS AND FRAMEWORK
>   M:	Oded Gabbay <ogabbay@kernel.org>
>   L:	dri-devel@lists.freedesktop.org
> diff --git a/drivers/accel/Kconfig b/drivers/accel/Kconfig
> index bdf48ccafcf21b2fd685ec963e39e256196e6e17..cb49c71cd4e4a4220624f7041a75ba950a1a2ee1 100644
> --- a/drivers/accel/Kconfig
> +++ b/drivers/accel/Kconfig
> @@ -30,5 +30,6 @@ source "drivers/accel/habanalabs/Kconfig"
>   source "drivers/accel/ivpu/Kconfig"
>   source "drivers/accel/qaic/Kconfig"
>   source "drivers/accel/rocket/Kconfig"
> +source "drivers/accel/thames/Kconfig"
>   
>   endif
> diff --git a/drivers/accel/Makefile b/drivers/accel/Makefile
> index 1d3a7251b950f39e2ae600a2fc07a3ef7e41831e..8472989cbe22746f1e7292d2401fa0f7424a6c15 100644
> --- a/drivers/accel/Makefile
> +++ b/drivers/accel/Makefile
> @@ -5,4 +5,5 @@ obj-$(CONFIG_DRM_ACCEL_ARM_ETHOSU)	+= ethosu/
>   obj-$(CONFIG_DRM_ACCEL_HABANALABS)	+= habanalabs/
>   obj-$(CONFIG_DRM_ACCEL_IVPU)		+= ivpu/
>   obj-$(CONFIG_DRM_ACCEL_QAIC)		+= qaic/
> -obj-$(CONFIG_DRM_ACCEL_ROCKET)		+= rocket/
> \ No newline at end of file
> +obj-$(CONFIG_DRM_ACCEL_ROCKET)		+= rocket/
> +obj-$(CONFIG_DRM_ACCEL_THAMES)		+= thames/
> \ No newline at end of file
> diff --git a/drivers/accel/thames/Kconfig b/drivers/accel/thames/Kconfig
> new file mode 100644
> index 0000000000000000000000000000000000000000..50e0b6ac2a16a942ba8463333991f5b0161b99ac
> --- /dev/null
> +++ b/drivers/accel/thames/Kconfig
> @@ -0,0 +1,26 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +config DRM_ACCEL_THAMES
> +	tristate "Thames (support for TI C7x DSP accelerators)"
> +	depends on DRM_ACCEL
> +	depends on TI_K3_R5_REMOTEPROC || COMPILE_TEST

COMPILE_TEST part shouldn't be needed here, TI_K3_R5_REMOTEPROC can be built
under COMPILE_TEST so TI_K3_R5_REMOTEPROC would just be enabled to test.

> +	depends on RPMSG
> +	depends on MMU
> +	select DRM_SCHED
> +	select DRM_GEM_SHMEM_HELPER
> +	help
> +	  Choose this option if you have a Texas Instruments SoC that contains
> +	  C7x DSP cores that can be used as compute accelerators. This includes
> +	  SoCs such as the AM62A, J721E, J721S2, and J784S4.
> +
> +	  The C7x DSP cores can be used for general-purpose compute acceleration
> +	  and are exposed through the DRM accel subsystem.
> +
> +	  The interface exposed to userspace is described in
> +	  include/uapi/drm/thames_accel.h and is used by the Thames userspace
> +	  driver in Mesa3D.
> +
> +	  If unsure, say N.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called thames.
> diff --git a/drivers/accel/thames/Makefile b/drivers/accel/thames/Makefile
> new file mode 100644
> index 0000000000000000000000000000000000000000..7ccd8204f0f5ea800f30e84b319f355be948109d
> --- /dev/null
> +++ b/drivers/accel/thames/Makefile
> @@ -0,0 +1,9 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +obj-$(CONFIG_DRM_ACCEL_THAMES) := thames.o
> +
> +thames-y := \
> +	thames_core.o \
> +	thames_device.o \
> +	thames_drv.o \
> +	thames_rpmsg.o
> diff --git a/drivers/accel/thames/thames_core.c b/drivers/accel/thames/thames_core.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..92af1d68063116bcfa28a33960cbe829029fc1bf
> --- /dev/null
> +++ b/drivers/accel/thames/thames_core.c
> @@ -0,0 +1,155 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Copyright 2026 Texas Instruments Incorporated - https://www.ti.com/ */
> +
> +#include "linux/remoteproc.h"
> +#include <linux/dev_printk.h>
> +#include <linux/err.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/completion.h>
> +#include <linux/jiffies.h>
> +#include <linux/rpmsg.h>
> +
> +#include "thames_core.h"
> +#include "thames_device.h"
> +#include "thames_rpmsg.h"
> +
> +/* Shift to convert bytes to megabytes (divide by 1048576) */
> +#define THAMES_BYTES_TO_MB_SHIFT 20

Seems unused/unneeded.

[...]

> +
> +static const struct rpmsg_device_id thames_rpmsg_id_table[] = { { .name = THAMES_SERVICE_NAME },
> +								{} };
> +

Some odd formatting here.

> +static struct rpmsg_driver thames_rpmsg_driver = {
> +	.drv = {
> +		.name = "thames",
> +		.owner = THIS_MODULE,

Above line shoulnd't be needed.

Andrew